(AP) -- A top House lawmaker says those who want to harm the U.S. are already changing their behavior after leaks about classified U.S. surveillance programs.

The House intelligence chairman, Republican Rep. Mike Rogers, says it's part of the damage from disclosures by National Security Agency contractor Edward Snowden of two NSA programs that collect millions of telephone records and track Internet activity. He gave no details.

Top committee Democrat, C.A. Dutch Ruppersberger of Maryland says he's concerned that Snowden fled to Hong Kong, because of China's spying on the U.S.

They spoke after meeting NSA director Gen. Keith Alexander, who says he hopes to declassify details of dozens of attacks allegedly disrupted by the programs. Alexander says they don't want to "cause another terror attack by giving out too much information."